In the United States, each year food-borne illness affects about 6 to 80 million people, causing 9,000 deaths and an estimated cost of 5 billion dollars. Outbreaks of food-borne pathogens including Listeria monocytogens, Salmonella gaminara and E. coli 0157:H7 are of great concern to the food industry and the general public because they are reported present in poultry, meat and fresh fruits and vegetable products (Altekruse et al., 1994; Mishu et al., 1993). In particular, Listeriosis causes miscarriages and result in meningitis in patients with chronic underlying disease (Mishu et al., 1993); Salmonella can cause septicemia and produce typhoid or typhoid like fever in humans and E. coli 0157:H7 produces potent toxins causing damage to the lining of the intestine leading to acute hemorrhagic colitis, hemolytic uremia syndrome, and thrombotic thrombocytopenic purpura.
During 2001, a total of 13,705 laboratory-diagnosed cases of 10 food-borne diseases under surveillance were identified including 5,198 of Salmonella, 565 of E. coli 0157:H7 and 94 of Listeria (Center of Disease Control, 2002). Post-processing contamination of microorganism on the surface of food products led to recalls and consequent economic losses for the food industry. During January 1999 to October 2000, 63 of 97 Class I recalls of cooked/ready-to-eat meats were due to Listeria contamination. E. coli 0157:H7 was responsible for outbreaks involving fermented meat products (Tilden et al., 1996) and fresh products (Besser et al., 1993). While 32,021 Salmonella isolates were reported to the Public Health Laboratory Information System during 2000. Therefore, simple economical and effective means of inhibiting the growth of food-borne pathogens in food products is a longfelt need.
Edible films can increase the shelf-life of foods by providing barring properties against migration of moisture, gases, and vapor, functioning as a carrier of food ingredients additives and antimicrobial agents and offering mechanical protection to foods. However, there is limited knowledge about the utilization of edible films as carriers for the release of antimicrobials at varying rates to enhance pathogens inhibition and extend product shelf-life.
Components of edible films and coating are divided into three categories, including hydrocolloids, lipids and composites. Suitable hydrocolloids include proteins and carbohydrates. Proteins, lipid, polysaccharide and composite are based on the nature of the material used for film production. Each film or coating type provides its own unique functional characteristics and is best suited to a specific food application.
Plasticizers are necessary to produce protein or polysaccharide-based films that possess a desirable mechanical strength and flexibility for handling (Torres, 1994). Glycerol is one of the most commonly used plasticizer for producing films. In order to produce an easily handled film, usually, 25–50% glycerol is required. However, edible films comprising this concentration of glycerol can impart a faint sweet flavor. Yet, films with bland taste are desirable for multipurpose applications. Therefore, an edible film with limited glycerol content that inhibits a wide spectrum of pathogens and increases shelf-life is desirable.
Edible film coating can protect fresh produce from microbial spoilage delay ripening and extend shelf-life (Brody 2002). Color is a primary actor affecting consumer selection of fresh produce (Good 2002). Therefore, coating with edible films to prevent survival of pathogen on the surface of fresh produce should not have any adverse effect in masking the color.
Discussion or citation of a reference herein shall not be construed as an admission that such reference is prior art to the present invention.